Human Serum Albumin (HSA) constitutes 57-71% of total serum protein. Depletion or removal of HSA provides several advantages including allowing for the enhanced detection of the remaining proteins that are present in lower concentration.
Typically, albumin has been removed from serum or plasma by one of two methods. First, albumin may be removed by antibodies using standard affinity chromatography. An advantage of standard affinity chromatography may be theoretical specificity and tight ligand association and binding. Disadvantages include the high cost and the possibility of immobilization and, hence, depletion of additional proteins through secondary interactions. A second method involves the use of Cibacron Blue attached to typical column matrices such as Sephadex. For example, so-called “swell-gel” columns are currently sold for albumin depletion based on the Cibacron Blue bonding. This method has disadvantages in that it achieves weaker binding of the albumin, and many other proteins also bind to the dye, i.e., lack of specificity. Cibacron Blue bonding is described in further detail by S. T. Thompson, et al., “Blue Dextran-Sepharose: An Affinity Column for the Dinucleotide Fold in Proteins,” Proc. Natl. Acad. Sci. 72: 669-672 (1975) and J. Travis, et al., “Isolation of Albumin from Whole Human Plasma and Fractionation of Albumin-Depleted Plasma,” Biochem. J 157: 301-306 (1976).
Attempts have been made to more specifically bind HSA to a support and thereby reduce the albumin content in serum. For example, a method has been described using an antibody ligand to bind human serum albumin. This ligand is disadvantageous in that the capacity of the device is quite low.
Thus, there exists in the art a need for an effective method of depleting albumin from blood, serum and/or plasma samples.